Vehicle position detection of the prior art involved receiving information emitted from a GPS or beacon, analyzing that information and then detecting the position of the vehicle. Since position detection using a GPS or beacon requires that electromagnetic waves emitted by the GPS or beacon be received, in the case of an object being present that obstructs electromagnetic waves between the electromagnetic device transmission apparatus and the reception apparatus installed in the vehicle, there is the problem of it no longer being possible to detect vehicle position. This type of system cannot be used at all by robots and so forth that move only indoors. Consequently, there are position detection apparatuses that detect the position of a vehicle based on sensor output values, or depending on the case, by matching road map data, by installing a distance sensor and azimuth sensor that detect wheel rotating speed on a vehicle. An example of this technology is described in Japanese Unexamined Patent Application, First Publication No. 9-243389.
However, in addition to it being necessary to provide detailed road map data inside the apparatus, since the detection results of this position detection apparatus contains error in the output values of the distance sensor and azimuth sensor, if position detection according to the output values of the distance sensor and azimuth sensor alone continues for a long period of time, the detection error ends up accumulating resulting in the problem of the detected vehicle position differing greatly from actual vehicle position. In addition, during movement of a humanoid robot that moves by the use of legs indoors in particular, although it is necessary for the robot itself to determine the relative locations of walls and columns, the position detection apparatus of the prior art has the problem of encountering difficulty in autonomous movement since it is difficult to determine relative positional relationships with the surrounding environment.